1. Field of the Invention
This invention generally relates to a bicycle control system. More specifically, the present invention relates to a bicycle control system that wirelessly transmits control signals to control components on the bicycle.
2. Background Information
Bicycle control systems exist that wirelessly control bicycle components, such as the bicycle derailleur systems. In an example of such a control system, an upshift signal (e.g., a high signal) is transmitted continuously during the time that an upshift switch is operated, and a downshift signal (e.g., a pulse signal) is transmitted continuously during the time that a downshift switch is operated. However, it can be appreciated that the amount of electric power needed to output a high signal or pulse signal continuously when the upshift switch or downshift switch is operated is much greater than the amount of electric power needed to output such signals intermittently.
Accordingly, a bicycle control system can perform synchronous communication with the components of the system control (e.g., the bicycle derailleur system) so that the upshift and downshift signals need not be transmitted continuously while the upshift and downshift switches are operated. In an example of such a control system, a transmitter unit is associated with each shift switch, and outputs a signal representing the state of the associated shift switch at prescribed periods of time, for example, every 100 milliseconds. For instance, the transmitter associated with the upshift switch transmits a high signal at the prescribed period of time when the upshift switch is being operated at the time of signal transmission. Also, the transmitter associated with the upshift switch transmits a low signal at the prescribed periods of time when the upshift switch is not being operated. Similar transmissions occur for a downshift switch. When a receiver unit associated with a derailleur system (e.g., the rear derailleur system) receives the high signals output by the transmitter units of the upshift switch or downshift switch, the receiver unit outputs a shift commission signal to control the rear derailleur system to perform an upshift or downshift operation as appropriate.
As can be appreciated, if the operating time of the upshift or downshift switch is shorter than the length of time between prescribed transmission periods (e.g., less than 100 milliseconds), operation of the upshift or downshift switch can occur between prescribed transmission periods. In this event, the transmitter transmits the signals at times when the shift switch is not being operated and thus, an indication of the shifting operation will not be transmitted. Furthermore, even if the transmitter correctly transmits the signal, noise or other disturbances may interfere with the signal and thus, the receiver may not receive the signal. If any of these situations occur, the receiver will not receive the correct shifting signal and thus, will not shift the gear position correctly.
Shortening the time between prescribed transmission periods can potentially reduce the possibility that operation of a shift switch will be brief enough to occur between prescribed transmission periods, thus increasing the likelihood that at least one transmission will occur during a shift switch operation. Also, shortening the time between prescribed transmission periods increases the number of transmissions, thus increasing the likelihood that the receiver will receive a transmission indicating operation of a shift switch even in the presence of noise or other interferences. However, increasing the number of transmissions increases the electric power consumption by the transmitter, thus decreasing the efficiency of the control system.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved bicycle wireless control system. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.